Document processing devices are in widespread use in many businesses and academic settings. Such devices include copiers, scanners, printers and facsimile machines. Today, one or more functions associated with such devices are combined in a single unit, referred to as a multifunction peripheral (“MFP”) or multifunction device (“MFD”). MFPs are typically connected to a network to allow users to print remotely from their computers, scan documents that can be sent to a user's computer or a third party's computer (for example via email), copy documents, or fax documents to other people.
Users can control the operations of the MFP via a user interface that is displayed on a display of the MFP. In some instances, it is possible for other people nearby to directly observe the actions of the user at the MFP, for example by looking over the user's shoulder and observing the display and user interface of the MFP. In more sophisticated situations, it is possible for other people to use binoculars, cameras, or mobile computing devices to observe the user at the MFP. Unauthorized parties therefore may be able to observe the user and obtain information such as passwords used by the user at the MFP and sensitive information relating to a user's document. To avoid unwarranted surveillance, a user can shield the keypad, or another part of the display, by using their body to block another person's view, for example by cupping the user's hand over the keypad. However, this conspicuous behavior often draws the attention of other people and may not reliably prevent other people from observing the user's actions.
The disclosed proximity-based user interface system addresses these and other problems associated with displaying information on the display of a MFP.